Re: [PATCH v10 0/9] KVM: mm: fd-based approach for supporting KVM

[Kirill A. Shutemov]

On Sat, Jan 14, 2023 at 12:37:59AM +0000, Sean Christopherson wrote:
> On Fri, Dec 02, 2022, Chao Peng wrote:
> > This patch series implements KVM guest private memory for confidential
> > computing scenarios like Intel TDX[1]. If a TDX host accesses
> > TDX-protected guest memory, machine check can happen which can further
> > crash the running host system, this is terrible for multi-tenant
> > configurations. The host accesses include those from KVM userspace like
> > QEMU. This series addresses KVM userspace induced crash by introducing
> > new mm and KVM interfaces so KVM userspace can still manage guest memory
> > via a fd-based approach, but it can never access the guest memory
> > content.
> > 
> > The patch series touches both core mm and KVM code. I appreciate
> > Andrew/Hugh and Paolo/Sean can review and pick these patches. Any other
> > reviews are always welcome.
> >   - 01: mm change, target for mm tree
> >   - 02-09: KVM change, target for KVM tree
> 
> A version with all of my feedback, plus reworked versions of Vishal's 
> selftest,
> is available here:
> 
>   git@github.com:sean-jc/linux.git x86/upm_base_support
> 
> It compiles and passes the selftest, but it's otherwise barely tested.  There 
> are
> a few todos (2 I think?) and many of the commits need changelogs, i.e. it's 
> still
> a WIP.
> 
> As for next steps, can you (handwaving all of the TDX folks) take a look at 
> what
> I pushed and see if there's anything horrifically broken, and that it still 
> works
> for TDX?

Minor build fix:

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6eb5336ccc65..4a9e9fa2552a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -7211,8 +7211,8 @@ void kvm_arch_set_memory_attributes(struct kvm *kvm,
        int level;
        bool mixed;
 
-       lockdep_assert_held_write(kvm->mmu_lock);
-       lockdep_assert_held(kvm->slots_lock);
+       lockdep_assert_held_write(&kvm->mmu_lock);
+       lockdep_assert_held(&kvm->slots_lock);
 
        /*
         * KVM x86 currently only supports KVM_MEMORY_ATTRIBUTE_PRIVATE, skip
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 467916943c73..4ef60ba7eb1d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2304,7 +2304,7 @@ static inline void kvm_account_pgtable_pages(void *virt, 
int nr)
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
 static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t 
gfn)
 {
-       lockdep_assert_held(kvm->mmu_lock);
+       lockdep_assert_held(&kvm->mmu_lock);
 
        return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
 }
-- 
  Kiryl Shutsemau / Kirill A. Shutemov